Magnum struggles to prove Higgins' innocence after he becomes the prime suspect in the murder of his old boarding school nemesis, William Troubshaw.

Practicing to take part in an upcoming pro-am tennis tournament, Magnum is assigned by Robin Masters to protect a spoiled young tennis star who is receiving death threats. Thomas finds his patience tested by the girl's bratty behavior, but is pleased that the tournament sees him reunited with an old flame - who is the girl's main competitor, and thus the prime suspect.